Gauge adjusting means



M'arch'zl, l1944. Y s` KAHN v 24,344,882

' GAUGE ADJUSTING MEANS Filed sept.`11, 1942 Patented Mar. 21, 1944 GAUGE ADJUSTING MEANS Samuel Kahn, Bridgeport, Conn., assignor to Manning, Maxwell & 4Moore, Incorporated, New

York, N. Y., a corporation of New Jersey Application September 11, 1942, Serial N0. 457,922 Claims. (Cl. 'I3-109) This invention pertains to dial instruments, for example pressure gauges, dial thermometers or the like and relates more particularly to means for calibrating and adjusting such instruments.

Usually such instruments employ a Bourdon tube or the like as the motor means-the motion of the free end of the tube being multiplied for transmission to the index or pointer. Owing to the intrinsic variations in the specic properties of the materials used it is necessary, both during manufacture and in the course of ordinary conditions of use, to adjust the relationship between the Bourdon tube and the index so that the motion of the tube tip will be transmitted in proper ratio to the index and so that the desired range of values to be indicated will correspond to those designated by the index relatively to its cooperating graduated dial.

In the more usual instruments of this type, such adjustments can only be made after removal of the index or pointer and the dial. Consequently, in such prior types of instrument it has been necessary to make adjustments (bending parts, exchanging parts for others of different dimensions, or releasing and relatively moving parts which are normally clamped together) with the indicator and dial removed; then to replace the dial and pointer and observe the relation of the pointer relatively to the dial; and if necessary repeat these operations until by such trial and error a suiiiciently correct approximation has been arrived at. Since a pressure gauge is a delicate piece of mechanism, attempts by unskilled persons-to make such adjustments often result in serious injury to the mechanism. y

I am aware of the patent to Hopkins, No. 1,484,068, February .1.9, 1924, which describes how the entire gauge movement mechanism may be mounted to swing about the axis of the pointer -so that by rst removing the dial and index and then loosening retaining screws the gauge movement as a whole may be swung about the index staff thereby to calibrate the gauge, thus assuring proper initial position of the sector relatively to the pinion with which it meshes without necessitating more difficult operations. This arrangement thus provides improved and accurate means for making an initial calibration or the relatively infrequent recalibrations of the gauge necessitated by slow and permanent changes in the characteristics of the Bourdon tube, but does not avoid the necessity for removal of the dial and index prior to calibration.

Since gauges which are in constant use, particularlyif exposed to vibration, as when used on a locomotive, tend to get out of adjustment very quickly by reason of wear or gradual shifting of relatively adjustable parts, it is necesssary quite frequently to adjust the pointer relatively to the zero point of the dial or other fixed graduation in order to assure that the instrument will indicate the true pressure. Thus it is required by law that the gauges of locomotives be so adjusted at least once in three months.

The present invention has for its principal object the provision of means making possible a very accurate and fine adjustment of the pointer or index without requiring removal of the index or dial or even cf the transparent front panel and by the movement of a single readily accessible part. Since this adjustment may be made without removing the pointer from its stair or removing the dial, the results of the adjustment may be observed at once and accurate adjustment attained at the rst attempt.

As such a ne adjustment of the pointer requires but slight relative movements of the gauge parts, while on the other hand initial calibration or recalibration may require relatively large movements of the parts, itis, as a practical matter, undesirable to combine the two adjustments in a single element since a single adjustment means, designed to provide for line adjustment, would be too slow in its action for accomplishing the coarser adjustment of initial calibration. Accordingly, a further object of the invention is to provide an instrument of this type wherein provision is made for coarse adjustment for calibration, and further and additional means is provided for obtaining the desired iinal and fine or micrometer adjustment, the two adjusting means being combined in a single, simple, inexpensive, durable and reliable construction.

Other and further objects and advantages of the invention will be pointed out in the following more detailed description and by reference to the accompanying drawing wherein Fig. 1 is a fragmentary front elevation of a dial instrument, for example a pressure gauge, embodying the present invention; i

Fig. 2 is a fragmentary section substantially on the line 2-2 of Fig. 1, with certain parts omitted; Y

Fig. 3 is a front, elevation of a supporting element for the movement mechanism of the instrument;

Fig. 4 is a fragmentary section on the same planetas Fig. 2 but tolarger scale showing details of construction;

Fig. 5 isa perspective View of an adjusting tube B. The opposite lever constituting an element of the novel mechanism; and

Fig. 6 is a section on line 6--6 of Fig. 1.

Referring to the drawing, the numeral I designates an instrument of the class described, for instance a dial thermometer or pressure gauge, having a casing which may be of any conventional type but which is preferably of the kind disclosed in the patent to Graesser et al., No. 2,271,423, dated January 27, 1942. This casing comprises the side wall 2, the rear wall 3 and the front g.

panel 4, the latter being of transparent material, for instance glass or a synthetic resin. This case is preferably substantially ai r-tight to `vform a suitable enclosure for the operative parts of the instrument. At a suitable point the case Vis pro'- vided, either in the rear wall 3 or the side wall 2 (as here shown at the lower part of the side wall) with an opening for the reception 'of the support 5 having the screw-threaded nipple portioni for attachment toa conductor for pressure fluid. This support 5 is furnished with a bracket portion l disposed within the casing, usually againstthe inner surfaceof the rear wall 3, and having openings for the reception of attaching 'screws or bolts 8 by means of which the casing is rigidly secured to the support. y The support is also provided witha socket portion B in which is rigidly secured in a leak-tight manner the fixed end I9 of the Bourdon tube B it being understood that this Bourdon tube is here shown merely by way of example of a pressure fluid moto-r of a conventional'type.

The support 5 also comprises an upwardly directed post I I whose upper end is preferably more or less disk-like to form the pad I2 to which the )movement mechanism is secured. As here illustrated (Fig 2) this pad I2 is 4'provided at its center with an aperture I3. Coaxial with'the pad and with the opening vI3 isa supporting plate I4 preferably made of thin spring metal, for example steel, and which is provided with a pair of arcuate slots I5 and Iii concentric with an opening I'I at the center of the plate. This opening II receives the 'inner or rear end which projects into the aperture and which forms the rear bearing for the index staff, hereinafter referred to.

The movement mechanism is carried by a frame 'comprising the rigid rear plate I9 andthe rigid front plate 2D (Fig. l), said plates, if desired, being of the same configuration and being' held in rigidly vspaced relation by means `or shouldered posts, one ofw'hich is indicated'at ZI. These plates I9 and 2i) are furnished with aligned bearings for the opposite ends of a staff -22 to which is secured vthe sector lever arm 23, said arm being connected by means of the link 24 to the tip bracket 25 attached to the Afree end of the Bourdon end -of the lever arm 23 carries the sector gear 25 (the arm 23 being adinstable in 1ength,if desired,in accordance with the usual practice), said sector gear 26 meshing with a pinion 21 fixed to the index staff, the rear er1-d 0f which nds a bearing in the bushing I8 above referred to, its forward portion turning in a bearing in the frontplate 20 of the movement frame. The pointer or index 29 is secured tothe 'forward end of the lindex staff 26 which projects forwardly through an opening inthe graduated dial Sil which, as here shown, is supported by one vor more rigid posts V3l secured to an extension or extensions I2a (Fig. 2) of the pad I'-2. Y

A screw 32, having a large flat head, passes 'through an opening in a bracket member 33,

portion of a bushing IB ing a slight clearance between it and the front surface of the plate iS, thus permitting the frame `to turn freely about the axis of the bushing i8.

The slot I6 in the supporting disk or plate I4 is extended as indicated at |62, Ib and EBC, so as to define an arcuate, resilient tongue integral ai; one end with the body of the plate and having A Vits other end free to be flexed to a greater or lesser radius of curvature. The free end of this spring tongue is provided with an aperture 3B which receives a pintle 31 (Fig. 6) preferably formed by rvstriking rearwardly the metal of the rear plate I9 of the movement; frame, such pintle thus constituting a pivotal connection between the frame and the tongue 35.

The supporting plate or disk I4 is also provided with an opening 38 which receives a pivot pin 3`9 (Fig. 1) forming the fulcrum for a bell crank' lever (Fig. 5) comprising a short arm 40 whose lfree endengages an abutment shoulder M (Fig. 1)

integral with the rear plate i9 of Athe movement frame. This bell crank lever also has an elongate l"I'hescrew d4 projects at its forward end through an opening 46 in the dial and is provided at its forward endvwith convenient means whereby it may be turned, for instance, a screw driver slot 41. Since this slot is forward of the dial it is possible to turn the screw without removing the dial.

v The rear portion of this screw (rearwardly ofthe conical head '53) passes freely through the arcuate slot I6 in the plate l and is threaded at A5 (preferably with a fine Aor low pitch thread). The threaded portion vof the screw engages a threaded bore in the pad I2. Preferably the screw projects beyond the pad and into an opening 4S in the rear-l wall of the casing, said openirg 4Q being of larger diameter than the screw. The

screw Vis Vfurnished with a xed collar or abut- Vment 43 at its vrear end Vthereby to limit the forward movement of the screw. This abutment 48 is pinned or otherwise xed to the rear end of Vthe screw and is lprovided with a screw driver slot -or other means for turning it, thereby making it possible to calibrate or readjust the `pointer from the outside rear of the case when'the latter is accessible.

The'initial calibration of the instrument for obtammg the proper angular relation of the link 24 land lever '23 is -made before the dial is put in position. VTo'calibrate the device, the screw 32 is flrsty loosened, thus vpermitting the supporting -disk I4, together with allof the parts carried thereby, to be swung aboutthe axis of the index staif. Such movement of 'the frame, as vdescribed inthe above patent to k'I-Iopkins, vprovides convenient means Yfor calibrating the vinstrument substitution of parts of different sizes.

without necessitating the bending of parts or the After the instrument has thus been properly calibrated,

the screw 32 is tightened, thus. holding the supporting plate I4 in proper position where it may remain during the entire life of the instrument. After such relatively coarse calibration, the dial is put in place and the pointer or index is mounted on the iront of the index staii. Then -by turning the screw 44, the conical head 43 is vcaused to advance or retreat from the arm 42 of thebell crank lever, thus rocking thelever and by minute and substantially micrometric motion .swinging the movement frame relatively to the plate I4 about the axis of the index staiT. Since such movement is resiliently opposed by the spring tongue 35, proper contact of the conical surface 43 with the lever arm 42 is assured regardless of the direction of rotation of the screw.

By the employment of screw threads 45 of low pitch, it is possible to retain the adjustment thus made for substantially any period of time regardless of the conditions of use of the instrument or the amount of vibration to which it may be subjected. With this construction it is thus possible to adjust the pointer with the greatest accuracy and by the mere turning of the screw 44 and Without necessitating the loosening of any parts prior to such adjustment or the tightening or clamping of parts after adjustment.

While one desirable embodiment of the invention has been herein disclosed by illustration and description, it is to be understood that the invention is not necessarily limited to this precise embodiment but is to be regarded as broadly inclusive of any and all equivalents falling within the terms of the appended claims.

I claim:

1. In combination in a dial instrument having an outer casing provided with a transparent panel and which houses a graduated dial, a motor device, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said stair and a pointer mounted on the stan for cooperation with the dial, a support for the movement mechanism, said support being mounted to turn about the axis of the index stati, thereby to permit calibration of the instrument, means for retaining the support in adjusted position, the movement mechanism being mounted on said support to turn about the axis of the index stair relatively to the support, and means for turning the movement mechanism relatively to the support and for retaining it in adjusted position thereby accurately to adjust the position of the pointer relatively to the dial.

2. In combination in a dial instrument having an outer casing provided with a transparent panel and which houses a graduated dial, a motor-device, a movement mechanism comprising an index staff and connections for transmitting mo- Vtion from the motor device tosaid stai and a pointer mounted on the staff for cooperation with the dial, a support for the movement mechanism, said support being mounted to turn about the axis of the index staff thereby to permit calibration of the instrument, means for retaining the support in adjusted position, the movement mechanism being mounted on the support to turn relatively to the latter about the axis of the index stair, and micrometer means for turning the movement mechanism relatively to the support thereby to adjust the pointer relatively to the dial graduations.

.3 3. In combination in a dial instrument having an outer casing provided with a transparent panel and which houses a graduated dial, a motor device, a movement mechanism comprising an index staff, a frame carrying bearings for said stair and connections for transmitting motion from the motor device to said stai and a pointer mounted on the staff for cooperation with the dial, a support for the movement mechanism arranged to turn about the axis of the index staff, means for retaining the support in adjusted position, the frame of the movement mechanism being mounted on the support to turn relativelyto the latter about the axis of the index staff, micrometric means operative positively to turn the movement mechanism frame in one direction relatively to the staff for adjusting the pointer relatively to the dial, and resilient means connecting the movement frame to the support, said resilient means constantly tending to turn the movement frame in the opposite direction, the adjusting means comprising an actuating element accessible at the front of the dial. t

4. In combination in a dial instrument of the kind wherein an outer casing provided with a transparent panel houses a graduated dial, a motor device, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said stai, an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, means supporting the movement frame to turn about the axis of the index staff, and means for turning the movement frame, said latter means comprising a lever arranged to swing about a normally xed axis, said lever having an arm which engages a part of the movement frame at a point eccentric to the index staff, and an actuating element engaging the other arm of said lever and operative to swing the latter.

5. In combination in a dial instrument of the kind wherein an outer casing provided with a transparent panel houses a graduated dial, a motor device, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said stai, an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, the movement frame being mounted to swing about the axis of the index staff, vand means for swinging said frame comprising a lever turning about a normally iixed axis eccentric to the index stai, said lever having one arm which engages a portion ofthe movement frame, and wedge means engaging the other arm of the lever and operative to swing the latter.

6. In combination in a dial instrument of the kind wherein an outer casing provided with ai transparent panel houses a graduated dial, a motor device, a movement mechanism compris ing an index staff and connections for transmitting motion from the motor device to said staff, an index on the stair cooperable with the dial, and a. frame supporting the movement mechanism, the movement frame being mounted to swing about the index staff, and means for swinging the frame comprising a lever turning about a normally xed axis, said lever having two arms one of which engages the movement frame,

.and a cam surface engaging the other arm of the transparent panel houses a .graduated dial, a motor device, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said stan', an index on the stai cooperable with the dial, and

a frame supporting the movement mechanism, Y

yengages the movement frame, and a screw whose axis is substantial-1y parallel to that oi the index staff, said screw having a conical portion engagifng the other arm of the lever whereby axial advance or retraction of the screw swings the lever in one direction or the other.

8. In combination in a dial instrument of the kind wherein an outer casing provided with a transparent panel houses a graduated dial, a motor device, a movement mechanism comprising an index stair and connections for transmitting motion from the motor device to said stai, an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, the movement frame being arranged to turn about the axis of the index staff', spring means tending to swing the frame in one direction, and a lever forr swinging the frame in the opposite direction, said lever being pivoted to turn about a normally fixed axis and comprising an arm which engages the movement frame, and wedge means engaging the lever operative to swing the lever, thereby to turn the frame in opposition to the spring.

9. In combination in a dial instrument of the kind wherein an outer casing `provided with a transparent panel houses a graduated dial', a motor device, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said stall", an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, the movement frame being arranged to swing about the axis of the index sta-fi", spring means tending to swing the frame in one direction, a lever for swinging it in the opposite direction, said lever Ycomprising an arm which engages the frame, and a screw having threaded engagement with a xed part of the instrument and provided Awith a conical portion which constantly engages the lever.

1'0. In combination in a dial instrument of the kind wherein an outer casing provided with' a transparent panel houses a graduated dial, a y

motor device, a movement mechanism comprising an index staff and connectionsl for transmitting motion from the motor device to said staff, an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, the movement frame being arranged to turn about the axis of the index staff, spring .means tending to turn the frame in one direction, a lever for turning it in the opposite direction, said lever comprising two armsl one of which engages a part of the frame, a screw whose axis is substantially parallel to that of the index staff, said screw having threaded engagement with a fixed part of the instrument and having its forward end exposed in front of the'dial, the screw being provided with a conical portieri which engages the other Aarm of the lever.

l1. In combination in a dial instrument of the kindwherein an outer casing, provided witha transparent panel, houses a graduated dial, a

motor device, a movement mechanism comprising an index stair and connections for transmitting motion from the motor device to said stall, an index on the stai cooperable with the dial, and a frame supporting the movement mechanism, the movement frame being mounted to turn about the axis of the index staff, a spring tending to move the movement frame in one direction, a lever for turning the frame in the opposite direction, said lever comprising two arms one of which bears against the movement frame, and a screw whose axis is substantially parallel to that of the index stad, said screw having threaded engagementl with a iixed portion of the instrument, means limiting forward movement of .the screw, the forward portion of the screw passing through an aperture in the dial and being provided at its forward end with means for turning it, and a conical part fixed to the screw and constantly engaging the other arm of the lever.

' l2. in combination in a dial instrument of the kind wherein an outer casing, provided with a transparent front panel, houses a graduated dial, a motor dev-ice, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, a support for the movement frame having arcuate slots for the reception of retaining screws, said support comprising an integral spring tongue, the movement frame being arranged to swing about the axis of the index stall, pivot means uniting the movement frame to the free end of said spring tongue, a bell crank lever pivotally mounted on the support, one arm of vthe lever engaging a surface of the movement frame, and a screw having its axis substantially parallely to the axis of the index stai, said screw passing freely through one of said arcuate slots and having threaded engagement with a xed part of the instrument, said screw having a conical portion which engages the other arm of the lever, and means whereby said screw may be turned.

i3. A dial instrument oi the kind wherein an outer casing, provided with a transparent front panel, houses a graduated dial, a motor device, a movement mechanism comprising an index sten and connections for transmitting motion from the motor device to said staff and a pointer on the index staff, for cooperation with the dial, and wherein the entire movement mechanism is mounted for rotary movement about the axis of the index staff thereby to permit calibration of the instrument, characterized in having means for accurately adjusting the pointer relatively to the dial graduations, said pointer adjusting means comprising a lever having an actuating arm arranged to engage the movement mechan'sm, the lever `being mounted to turn about an axis parailel to the axis of the index staff, means tending. to keep the actuating arm of the lever in contact with the movement frame, a rotary conical wedge which constantly engages the other arm of the lever, and an actuating element for turning the wedge, said actuating element beng normally accessible from the exterior of the instrument casing.

In combination in a dial instrument of the kind wherein an outer casing provided with a transparent panel houses a graduated dial, a motor device, a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said staff,

an index on the staff cooperable with the dial, and a frame supporting the movement mechanism, the movement frame being arranged to swing about the axis of the index staff, spring means tending to swing the frame in one direction, a lever for swinging it in the opposite direction, said lever comprising anarm which engages the frame, and a screw having threaded engagement with a fixed part of the instrument and provided with a conical portion which constantly engages the lever, one end of said screw being disposed at the rear of and outside the instrument casing and having means at its rear end whereby it may be turned.

15. A dial instrument of the kind wherein an outer casing, provided with a transparent front panel, houses a graduated dial and a motor device, a support on which the casing and motor device are fixedly mounted, the casing also housing a movement mechanism comprising an index staff and connections for transmitting motion from the motor device to said stai, and a pointer on the index staff for cooperation with the dial,

a pad fixed within the casing, a forwardly projecting bushing supported by the pad, the forward end of the bushing constituting a rear bearing for the index staff, a support mounted for rotation upon the bushing, means normally holding the support stationary in adjusted position, a frame for the movement mechanism mounted on the bushing, the frame being rotatable relatively to the support, resilient means opposing rotation of the frame relatively to the support whereby rotation of the support relatively to the pad effects a relatively coarse calibration of the instrument while the rotation of the frame relatively to the support effects a relatively fine adjustment of the pointer with reference to the dial graduations, and manually actuable adjusting means operative to turn the frame relatively to the support and to retain it in adjusted position, said manually actuable adjusting means comprising an element which is normally behind the transparent panel but which is accessible at the front of the dial.

SAMUEL KAHN. 

